Radiometric and Radiogenic Heat Evaluation of Natural Radioactivity in Soil Around Solid Minerals Mining Environment in South-Eastern Nigeria

Radionuclides activity concentrations in soil around ten solid mineral mining sites have been investigated using sodium iodide [Na(TI)] gamma spectroscopy. Four soil samples and a control sample were collected from each of the selected sites for analyses. The obtained results showed mean concentration values of 33.2 Bq kg−1 for 226Ra, 100.7 Bq kg−1 for 40K and 77.7 Bq kg−1 for 232Th. The estimated radiological risk parameter results have shown average values of 67.5 ηGy h−1 for the Absorbed Dose Rate (DR), 82.8 μSv y−1 for the Annual Effective Dose Equivalent (AEDE), 151.4 Bq kg−1 for the Radium Equivalent (Raeq) and 457.1 mSv y−1 for the Annual Gonadal Equivalent Dose (AGED) which is highly comparable to the allowable WHO value of 300 mSv y−1 and the control value of 177.7 mSv y−1. The average Excess Life Cancer Risk (ELCR) value obtained was 289.6 × 10−6 and the control value 112.9 × 10−6. The average External Hazard Index (Hex), Internal Hazard Index (Hin), Representative Gamma index (Iγ), and Activity Utilization Index (AUI) obtained were 0.4, 0.5, 1.1 and 1.3, respectively. The Radiogenic Heat produced Q ranged from 248.4 pW kg−1 in Awkuke (ironstone mine) to 608.5 pW kg−1 in Ama-Echi (Silica mine) with an average heat value of 415.8 pW kg−1. The obtained result for lithology [clay] identification showed a mixed clay lithology type. The overall results were found to be higher when compared to previously reported values from similar mineral mining areas, which indicates radiological contamination. © 2018, Springer Nature Switzerland AG.